RS57941B1 - Method for producing cathode copper - Google Patents

Description

Description

Field of invention

[0001] This invention relates to a process for the production of cathode copper as defined in the preamble of independent patent claim 1.

[0002] The known production process for the production of cathode copper, which has a purity greater than 99.9%, from copper concentrate includes firstly melting the sulfide copper concentrate in the first pyrometallurgical phase in the first furnace for melting the suspension by partial oxidation of the copper concentrate to obtain the molten copper phase which is further oxidized in the second pyrometallurgical phase in the second furnace for melting the suspension to metallic copper, i.e. blister copper. A manufacturing process that uses a first and second slurry melting furnace is sometimes called a double flash process. Alternatively, copper sulphide concentrate can be directly smelted to metallic copper ie. blister copper in a direct-to-blister process in one pyrometallurgical phase performed in one slurry melting furnace. In both cases, the resulting blister copper is further refined in anode furnaces by flame refining to obtain molten anode copper, which is poured into anode molds to cast copper anodes. This known manufacturing process for the production of copper cathodes involves additionally further subjecting cast anodes to electrolytic refining in electrolytic cells to produce cathode copper.

[0003] Anodic waste is obtained in the production of cathode copper in two stages. Spent cast anodes from electrolytic refining form the main source of anode waste. Additionally, some of the cast anodes produced in the anode casting stage do not meet certain quality requirements and are therefore rejected. Spent cast anodes and rejected cast anodes contain, in terms of mass percentage, approximately 99% copper, which is about 15 to 20% of the total mass of primary copper produced. Therefore, this material must be recycled.

[0004] Typically, in smelters using Peirce-Smith (PS) converting, spent cast anodes and discarded cast anodes are introduced into PS-converters. It is simple to introduce spent cast anodes and discarded cast anodes there, and the excess heat produced by the conversion reactions is more than enough to melt the spent cast anodes and discarded cast anodes.

[0005] In modern slurry melting furnaces such as double flash and direct-to-blister furnaces, the option of introducing anode waste to convert is not available, as these furnaces are not Peirce-Smith converters. A common solution must therefore provide a separate furnace for melting spent cast anodes and discarded cast anodes using heat from burning fossil fuels. Fig. 1 shows an example of a process according to the state of the art, which process includes direct-to-blister melting.

[0006] The process for the production of anodic copper shown in Fig. 1 includes a melting phase that includes the introduction of feed material 1 containing sulfide copper, reaction gas 2 containing oxygen and material 3 for forming slag such as a melter into the reaction body 4 of the furnace 5 for melting the suspension by means of the burner 6 which is carried out on top of the reaction body 4 of the furnace 5 for melting the suspension, whereby the feed material 1 containing sulfide copper, reaction the oxygen-containing gas 2 and the slag-forming material 3 react in the reaction body 4 into blister copper 7 and slag. Blister copper 7 and slag 8 are collected in the precipitator 11 of the slurry melting furnace 5 to form a blister layer 9 containing blister copper 7 and a slag layer 10 containing slag 8 on top of the blister layer 9 in the precipitator 11 of the slurry melting furnace 5.

[0007] The process shown in Fig. 1 includes a phase of flame refining which includes the introduction of blister copper 7 obtained in the melting phase into the anode furnace 12 and flame refining of blister copper in the anode furnace 12 in order to produce molten anode copper 13 in the anode furnace.

[0008] The process shown in Fig.1 includes the phase of casting anodes which includes the introduction of anode copper 13 obtained in the phase of flame refining into molds 14 for casting anodes in order to produce cast anodes 15.

[0009] The procedure shown in Fig. 1 includes a phase 16 of quality control in order to divide the cast anodes 15 obtained in the anode casting phase into accepted cast anodes 17 and rejected cast anodes 18.

[0010] The process shown in Fig. 1 includes an electrolytic refining stage for subjecting the accepted cast anodes 17 to electrolytic refining in an electrolytic cell 19 to produce cathode copper 20, and as a by-product, spent cast anodes 21.

[0011] The process shown in Fig. 1 includes a recycling phase for recycling the anode copper of discarded cast anodes 18 and the anode copper of spent cast anodes 21. More specifically, the recycling phase of the process according to the prior art process shown in Fig. 1 includes the introduction of discarded cast anodes 18 and spent cast anodes 21 into a separate furnace 22 for melting waste in order to melt the discarded cast anodes 18 and of the spent cast anodes 21 in the waste melting furnace 22 and introducing the melt 23 of the copper anodes from the waste melting furnace 22 into the anode casting molds 14 in order to produce the cast anodes 15.

[0012] In the solution shown in Fig.1, discarded cast anodes 18 and spent cast anodes 21 are melted in a shaft furnace 22 to produce new cast anodes 15 from the materials of discarded cast anodes 18 and spent cast anodes 21. This is a simple solution that achieves the goal of recovering copper from discarded cast anodes 18 and spent cast anodes 21. Disadvantages of such a solution state of the art are the costs for the construction and operation of a separate furnace 22 for melting waste. Also from the point of view of energy consumption and greenhouse gas emissions, this known solution cannot be considered good.

[0013] Publication WO 2013/186440 A1 presents a process and assembly for refining copper concentrate.

[0014] Publication JP 2000239883 A presents a method for recycling material returned from anodes for casting, and the like, in copper refining, and a device for filling material returned from anodes for casting, and the like, into a refining furnace.

[0015] Publication JP H0978151 A presents the procedure of recycling useful metals from waste.

[0016] Publication WO 2004/005822 A1 presents a method and assembly for introducing an anode into a smelter.

Subject matter of the invention

[0017] The aim of this invention is to provide an efficient process for refining copper concentrate.

Brief description of the invention

[0018] The copper concentrate refining process of this invention is characterized by the definitions of independent patent claim 1.

[0019] Preferred examples of the execution of the procedure are defined in the dependent patent claims.

[0020] The present invention is based on the use of excess heat energy produced in slurry melting furnace reactions to melt cast anode rejects and spent cast anodes. In slurry smelting processes such as the double flash and direct-to-blister processes, there is often excess heat produced in the oxidation reactions in the slurry smelting furnaces, meaning that the reactions produce more heat than is needed to melt the copper concentrate. This is especially true in declining ore grades, since copper decline is usually accompanied by and tends toward Fe and S contents, resulting in more heat of reaction. Very often, excess thermal energy can even be a problem, causing a bottleneck in the slurry melting furnace. In that case, the aim of this invention is to recycle the anode waste efficiently and to absorb the excess heat in the reaction hull.

[0021] More specifically, in the process the rejected cast anodes and spent cast anodes are mechanically crushed to produce anode copper grain from the rejected cast anodes and spent cast anodes, and the anode copper grain is introduced into the reaction hull of the slurry smelting furnace. The goal is for the anode copper grains to melt their way down from the top of the slurry furnace reaction body to the slurry furnace clarifier, not in the slurry furnace clarifier. For this reason, the anode copper grain is preferably, but not necessarily, introduced from the roof structure of the reaction hull into the reaction hull to allow sufficient time to melt the copper grains in the reaction hull. Even if the goal of melting the anode waste in the reactor core is not fully achieved, the anode copper grain will be significantly heated in the reactor core, thus reducing the cooling effect that melting will have on the furnace bed.

[0022] If the slurry smelter is operated with reduced oxygen enrichment to counteract the additional heat in the copper concentrate, the heat for smelting the anode waste can be provided by increasing the oxygen enrichment in the slurry smelter. This increases the consumption of technical oxygen. In areas where oxygen is significantly cheaper than natural gas, this is a significant savings in operating costs. Oxygen consumption is also more sustainable than burning fossil fuels considering both the environmental impact and the availability of Earth's limited resources. Using a higher oxygen enrichment also results in a smaller gas volume in the slurry melting process, thus reducing certain process costs.

[0023] If there is additional thermal energy in the copper concentrate, and the burner must be operated at maximum oxygen enrichment due to bottlenecks in the outlet gas line, the heat absorption of the concentrate can be a limiting factor for the production rate. In this case, the smelting of anode waste will not result in increased energy consumption of any kind in the slurry smelting furnace. In contrast, the cooling effect introduced can help increase the production rate in the slurry melting furnace.

List of drawings

[0024] In the following, this invention will be described in more detail with reference to the drawings, of which

Fig.1 is a schematic view showing the principle of the procedure according to the state of the art

Fig. 2 is a schematic view showing the principle of the first example of performing the procedure,

Fig. 3 is a schematic representation showing another example of the execution of the procedure,

Fig. 4 is a schematic view showing the principle of the third example of performing the procedure,

Fig. 5 is a schematic view showing a fourth example of the execution of the procedure, i

Fig. 6 is a schematic view showing the fifth example of the execution of the procedure.

Detailed description of the invention

[0025] Fig. 2 to 6 show some examples of the execution of the procedure for the production of cathode copper.

[0026] The process includes a melting phase that includes the introduction of material 1; 1a, 1b containing sulfide copper such as sulfide concentrate 1a copper or melt 1b of finely divided copper and additionally reaction gas 2 containing oxygen and material 3 for forming slag such as melter in the reaction body 4 of the furnace 5; 5a, 5b for melting the suspension by means of the burner 6, which is carried out on top of the reaction body 4 of the furnace 5; 5a, 5b for melting the suspension.

[0027] In the melting phase of the process, material 1 containing sulfide copper, reaction gas 2 containing oxygen and material 3 for slag formation react in the reaction body 4 of the furnace 5; 5a, 5b to melt the slurry into blister copper 7 and slag 8, and the blister copper 7 and slag 8 are collected in the precipitator 11 of the slurry melting furnace 5 to form a blister layer 9 containing blister copper 7 and a slag layer 10 containing slag 8 on top of the blister layer 9 in the precipitator 11 of furnace 5; 5a, 5b for melting the suspension.

[0028] The method additionally includes a phase of flame refining which includes the introduction of blister copper 7 obtained in the melting phase into the anode furnace 12 and flame refining of blister copper 7 in the anode furnace 12 producing molten anode copper 13 in the anode furnace 12.

[0029] The process additionally includes an anode casting phase which includes the introduction of molten anode copper 13 obtained in the flame refining phase into anode casting molds 14 in order to produce cast anodes 15.

[0030] The procedure additionally includes a quality control phase 16 for the division of cast anodes 15 obtained in the anode casting phase into accepted cast anodes 17 and rejected cast anodes 18.

[0031] The process additionally includes an electrolytic refining phase, which includes subjecting the accepted cast anodes 17 to electrolytic refining in an electrolytic cell 19 for the production of cathode copper 20 and, as a by-product, spent cast anodes 21.

[0032] The process additionally includes a recycling phase for recycling the anode copper of discarded cast anodes 18 and the anode copper of spent cast anodes 21.

[0033] The recycling phase includes introducing the discarded cast anodes 18 and spent cast anodes 21 into a mechanical crusher 24 such as a crusher for mechanically crushing the discarded cast anodes 18 and spent cast anodes 21 to produce anode copper grain 25, and introducing the anode copper grain 25 into the reaction hull 4 of the furnace 5; 5a, 5b for melting the suspension by means 27 for introducing copper grains.

[0034] The method may include the introduction of grains 25 of anode copper into the reaction body 4 of the furnace 5; 5a, 5b for melting the suspension at some distance from the burner 6.

[0035] The method may include the introduction of grains 25 of anode copper into the reaction body 4 of the furnace 5; 5a, 5b for melting the suspension through the burner 6.

[0036] The method may include the introduction of grains 25 of anode copper into the reaction body 4 of the furnace 5; 5a, 5b for melting the suspension from the top of the reaction body 4 of the furnace 5; 5a, 5b for melting the suspension.

[0037] The method may include the introduction of grains 25 of anode copper into the reaction body 4 of the furnace 5; 5a, 5b for melting the suspension in the introduction point located between the connection point between the precipitator 11 and the reaction body 4 and the top of the reaction body 4, i.e. in the introduction point located at the vertical level between the connection point between the precipitator 11 and the reaction body 4 and the top of the reaction body 4.

[0038] The method may include introducing an additional inert gas such as nitrogen 26 into the reaction body 4 of the furnace 5; 5a, 5b for melting the slurry to prevent the hot gases from the furnace 5; 5a, 5b for melting the suspension enter means 27 for introducing copper grains.

[0039] The method may include a drying phase for drying the anode copper grains 25 in the drying means 28 before introducing the anode copper grains 25 into the reaction body 4 of the furnace 5 for melting the slurry, as shown in the embodiment shown in Fig.6.

[0040] The method may include a preheating phase for preheating the anode copper grains 25 in a heating medium (not shown in the drawings) before introducing the anode copper grains 25 into the reaction body 4 of the furnace 5 for melting the slurry.

[0041] The method may include the use of a screw dispenser to introduce the anode copper grains 25 into the furnace 5 for melting the slurry.

[0042] In the fourth and fifth examples of execution illustrated in Fig. 5 and 6, the procedure includes the introduction of the slag 8 obtained in the first stage of melting into the electric furnace 29 for refining the slag. The fourth and fifth examples of the process include a slag treatment stage for treating the slag 8 in the electric slag refining furnace 29 with a reducing agent 30 introduced in the electric slag refining furnace 29 to produce an electric furnace slag layer 31 containing electric furnace slag 32 and an electric furnace blister copper layer 33 containing electric furnace blister copper 34. The fourth and fifth examples of the procedure include the introduction of blister copper 34 from the electric furnace obtained in the slag processing phase into the anode furnace 12. The fourth and fifth examples of the procedure include the introduction of slag 32 from the electric furnace obtained in the slag processing phase into the means 35 for refining the final slag. The fourth and fifth exemplary embodiments of the process include a final slag refining stage for subjecting the electric furnace slag 32 to a final slag refining process to produce a waste slag 36 and a slag concentrate or other material 37 containing copper from the electric furnace slag 32. The fourth and fifth examples of performing the procedure include the introduction of slag concentrate or other material 37 containing copper obtained in the flotation phase into the reaction body 4 of the furnace 5 for melting the suspension.

[0043] The second example of execution shown in Fig.3 and the third example of execution shown in Fig.4 are so-called double flash procedures, whereby the first example of execution shown in Fig.2, the fourth example of execution shown in Fig.5, and the fifth example of execution shown in Fig.6 represent direct-to-blister procedures. It is obvious to one of ordinary skill in the art that the embodiments shown in Fig. 2, 5 or 6 may use the first slurry melting furnace 5a and the second slurry melting furnace 5b as shown in Figs. 3 and 4 and that the anode copper grain 25 may be introduced into at least one of the first slurry melting furnace 5a and the second slurry melting furnace 5b as shown in Figs. 3 and 4.

[0044] The first embodiment, the fourth embodiment, and the fifth embodiment shown in Fig. 2, 5 and 6 include the so-called direct-to-blister melting in the furnace 5 for melting the suspension. In the first example of execution, in the fourth example of execution, and in the fifth example of execution shown in Fig. 2, 5 and 6, where the melting phase includes the introduction of material containing sulfide copper in the form of copper sulfide concentrate 1a, reaction gas 2 containing oxygen and material 3 for forming slag into the reaction body 4 of the furnace 5 for melting the suspension by means of the burner 6, which is carried out on top of the reaction body 4 of the furnace 5 for melting the suspension. Copper sulfide concentrate 1a, oxygen-containing reaction gas 2 and slag-forming material 3 react in reaction hull 4 of furnace 5 to melt slurry into blister copper and slag 8. Melt 1b and slag 8 are collected in precipitator 11 of slurry melting furnace 5 to form melt layer 38 containing melt 1b and slag layer 10 containing slag 8 on top of the layer. 38 melting in the precipitator 11 furnace 5a for melting the suspension.

[0045] The second embodiment and the third embodiment shown in Fig. 3 and 3 include so-called double flash melting. In the second and third examples of execution shown in Fig.3 and 4, the melting phase includes the first melting phase which includes the introduction of copper sulfide concentrate 1a, reaction gas 2 containing oxygen and material 3 for forming slag into the reaction body 4 of the first furnace 5a for melting the suspension by means of the burner 6 which is carried out on top of the reaction body 4 of the first furnace 5a for melting the suspension. Copper sulfide concentrate 1a, oxygen-containing reaction gas 2, and slag-forming material 3 react in the reaction body 4 of the first slurry melting furnace 5 into melt 1b and slag 8. Melt 1b and slag 8 are collected in the precipitator 11 of the first slurry melting furnace 5 to form a melt layer 38 containing melt 1b and a slag layer 10 containing slag 8. on top of the melt layer 38 in the precipitator 11 of the first furnace 5a for melting the suspension.

[0046] In the second and third examples of execution shown in Fig.3 and 4, the melting phase includes an additional second melting phase which includes the introduction of the melt 1b obtained in the first melting phase, the reaction gas 2 containing oxygen and the material 3 for forming slag into the reaction body 4 of the second furnace 5b for melting the suspension by means of the burner 6 which is carried out on top of the reaction body 4 of the second furnace 5b for melting the suspension. The melt 1b, the reaction gas 2 containing oxygen and the slag forming material 3 react in the reaction hull 3 of the second furnace 5b for melting the slurry into blister copper 7 and slag 8. The blister copper 7 and slag 8 are collected in the precipitator 11 of the second slurry melting furnace 5 to form a layer containing blister copper 7 and a slag layer 10 containing slag 8 on top of the layer in the precipitator 11 other furnaces 5 for melting the suspension.

[0047] In the second embodiment shown in Fig. 3, the anode copper grain 25 is introduced in the recycling phase into the reaction body 4 of the second furnace 5b for melting the suspension.

[0048] In the third embodiment shown in Fig. 4, the anode copper grain 25 is introduced in the recycling phase into the reaction body 4 of the first furnace 5a for melting the suspension. In this process, the anode copper grain 25 will have an effect on the condition of the oxygen-containing reaction gas 2 which must be taken into account in the control of the process.

[0049] It will be apparent to one of ordinary skill in the art that as technology advances, the basic idea of the present invention can be implemented in various ways. The present invention and its embodiments are therefore not limited to the examples described above, but may vary within the scope of the claims.

Claims (12)

Patent claims 1. A process for the production of cathode copper, wherein the process includes the melting phase which includes the introduction of material (1; 1a, 1b) containing sulphide copper such as sulphide concentrate (1a) of copper or melt (1b) of finely divided copper and additionally reaction gas (2) containing oxygen and material (3) for the formation of slag in the reaction body (4) of the furnace (5; 5a, 5b) for melting the suspension by means of a burner (6) which is carried out on top of the reaction body (4) of the furnace (5; 5a, 5b) for melting the slurry, wherein the material (1; 1a, 1b) containing sulfide copper, the reaction gas (2) containing oxygen and the material (3) for forming slag react in the reaction body (4) of the furnace (5; 5a) for melting the slurry into blister copper (7) and slag (8), and collecting the blister copper (7) and slag (8) in the precipitator (11) of the furnace (5; 5a, 5b) for melting suspension to form a blister layer (9) containing blister copper (7) and a slag layer (10) containing slag (8) on top of the blister layer (9) in the precipitator (11) of the slurry melting furnace (5; 5a, 5b), a flame refining stage which includes introducing the blister copper (7) obtained in the melting stage into the anode furnace (12) and flame refining the blister copper (7) in the anode furnace (12) producing molten anode copper (13) in the anode furnace (12), an anode casting stage which involves introducing the molten anode copper (13) obtained in the flame refining stage into anode casting molds (14) to produce cast anodes (15), stage (16) of quality control to divide the cast anodes (15) obtained in the anode casting stage into accepted cast anodes (17) and rejected cast anodes (18), an electrolytic refining step involving subjecting the accepted cast anodes (17) to electrolytic refining in an electrolytic cell (19) to produce cathode copper (20) and, as a by-product, spent cast anodes (21), and the recycling phase for the recycling of anode copper of discarded cast anodes (18) and anode copper of spent cast anodes (21), time, which includes a recycling step that includes introducing the discarded cast anodes (18) and spent anodes into a mechanical crusher (24) for mechanically crushing the discarded cast anodes (18) and spent cast anodes (21) to produce anode copper grains (25), and introducing anode copper grains (25) into the reaction body (4) of the furnace (5; 5a, 5b) using slurry melting means (27) for the introduction of copper grains. 2. The method according to claim 1, characterized by the introduction of grains (25) of anode copper into the reaction body (4) of the furnace (5; 5a, 5b) for melting the suspension at some distance from the burner (6). 3. The method according to claim 1 or 2, characterized by introducing grains (25) of anode copper into the reaction body (4) from the top of the reaction body (4) of the furnace (5; 5a, 5b) for melting the suspension. 4. The method according to any one of claims 1 to 3, characterized by introducing grains (25) of anode copper into the reaction body (4) of the furnace (5; 5a, 5b) for melting the slurry at the introduction point located between the connection point between the precipitator (11) and the reaction body (4) and the top of the reaction body (4). 5. The method according to claim 1, characterized by introducing grains (25) of anode copper into the reaction body (4) of the furnace (5; 5a, 5b) for melting the suspension with a burner (6). 6. A method according to any one of claims 1 to 5, characterized by introducing an additional inert gas such as nitrogen (26) into the reaction body (4) of the slurry melting furnace (5; 5a, 5b) to prevent hot gases from the slurry melting furnace (5; 5a, 5b) from entering the means (27) for introducing copper grains. 7. The method according to any one of claims 1 to 6, characterized by a drying phase for drying the anode copper grains (25) in the means (28) for drying before introducing the anode copper grains (25) into the reaction body (4) of the furnace (5) for melting the suspension. 8. The method according to any one of claims 1 to 7, characterized by the use of a screw dispenser for introducing grains (25) of anode copper into the furnace (5) for melting the suspension. 9. The method according to any one of claims 1 to 8, characterized by introducing the slag (8) obtained in the melting phase into the electric slag refining furnace (29), the slag processing phase to process the slag (8) in the electric slag refining furnace (29) with a reducing agent (30) to produce in the electric slag refining furnace (29) a layer (31) of electric furnace slag containing slag (32) from the electric furnace and a layer (33) of blister copper from an electric furnace containing blister copper (34) from an electric furnace, introducing blister copper (34) from the electric furnace obtained in the slag processing stage into the anode furnace (12), introducing slag (32) from the electric furnace obtained in the slag processing stage into the flotation means (35), the flotation stage for subjecting the slag (32) from the electric furnace to a flotation process to produce waste slag (36) and concentrate (37) of the slag slag (32) from the electric furnace, and by introducing the slag concentrate (37) obtained in the flotation phase into the reaction body (4) of the furnace (5) for melting the suspension. 10. The method according to any one of claims 1 to 9, characterized by the melting phase, which includes the first melting phase, which includes the introduction of copper sulfide concentrate (1a), reaction gas (2) containing oxygen and material (3) for forming slag into the reaction body (4) of the first furnace (5a) for melting the suspension by means of a burner (6) which is carried out on top of the reaction body (4) of the first furnace (5) for melting the suspension, wherein the copper sulfide concentrate (1), reaction gas (2) containing oxygen and material (3) to form slag react in the reaction body (4) of the first slurry melting furnace (5) into melt and slag (8), and collecting the melt and slag (8) in the precipitator (11) of the first slurry melting furnace (5) to form a melt layer containing the melt and a slag layer (10) containing slag (8) on top of the layer in the precipitator (11) of the first slurry melting furnace (5), and by the melting phase, which includes the second melting phase, which includes the introduction of the melt (1b) obtained in the first melting phase, the reaction gas (2) containing oxygen and the material (3) for forming slag into the reaction body (4) of the second furnace (5b) for melting the suspension by means of the burner (6) which is carried out on top of the reaction body (4) of the second furnace (5) for melting the suspension, whereby the melt, the reaction gas (2) containing oxygen and the material (3) for forming the slag reacts in the reaction hull (4) of the second slurry melting furnace (5) into blister copper (7) and slag (8), and collecting the blister copper (7) and slag (8) in the precipitator (11) of the second slurry melting furnace (5) to form a layer containing blister copper (7) and a slag layer (10) containing slag (8) on top of the layer in the precipitator (11) of the second slurry melting furnace (5). 11. The method according to claim 10, characterized by the introduction of grains (25) of anode copper in the recycling phase into the reaction body (4) of the first furnace (5a) for melting the suspension. 12. The method according to claim 10 or 11, characterized by the introduction of grains (25) of anode copper in the recycling phase into the reaction body (4) of the second furnace (5b) for melting the suspension.